66145 has 4 divisors (see below), whose sum is σ = 79380. Its totient is φ = 52912.

The previous prime is 66137. The next prime is 66161. The reversal of 66145 is 54166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 51984 + 14161 = 228^2 + 119^2 .

It is a cyclic number.

It is not a de Polignac number, because 66145 - 2³ = 66137 is a prime.

It is a super-2 number, since 2×66145² = 8750322050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6610 + ... + 6619.

It is an arithmetic number, because the mean of its divisors is an integer number (19845).

2⁶⁶¹⁴⁵ is an apocalyptic number.

It is an amenable number.

66145 is a deficient number, since it is larger than the sum of its proper divisors (13235).

66145 is a wasteful number, since it uses less digits than its factorization.

66145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13234.

The product of its digits is 720, while the sum is 22.

The square root of 66145 is about 257.1867026112. The cubic root of 66145 is about 40.4419734991.

The spelling of 66145 in words is "sixty-six thousand, one hundred forty-five".